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DOE OSTI2024

AMPP-4 Metric Dashboard

The AMPP-4 Metric Dashboard is an interactive tool used for visualizing key performance indicators and milestones for the various teams in the Material Recovery & Recycle (AMPP-4) group. This dashboard provides current group data for FY25 tracking purposes. The dashboard is organized by various chapters: 1) AMPP-4 overview, 2) Scheduling, and 3) individual chapters for each team. AMPP-4 supports 7 teams, where the day- and swing-shift aqueous demolition teams are treated as one team for the purpose of metric tracking. The dashboard is used internally to monitor the success and health of the AMPP-4 teams. Additionally, the dashboard can be used externally to support programmatic reporting to sponsors and aid in future milestone and work package planning.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS1982

High dispersion far ultraviolet spectra of cool stars

Recent far ultraviolet high dispersion spectra of two cool supergiant stars, Beta Dra (G2 Ib) and Alpha Ori (M2 Iab) are examined in the context of current questions regarding stellar chromospheres, coronae and mass loss. These stars show very different outer atmosphere structure. Beta Dra has a geometrically thin transition region with bright emission lines of 100,000 K plasma that are red-shifted, indicating downflow in magnetic flux tubes. By contrast, Alpha Ori has a cool extended chromosphere and circumstellar envelope with large mass loss.

Stencel, R. E.↗

NASA NTRS1982

Free-electron laser from wave-mechanical beats of 2 electron beams

It is possible, though technically difficult, to produce beams of free electrons that exhibit beats of a quantum mechanical nature. (1) the generation of electromagnetic radiation, e.g., light, based on the fact that the beats give rise to alternating charge and current densities; and a frequency shifter, based on the fact that a beam with beats constitutes a moving grating. When such a grating is exposed to external radiation of suitable frequency and direction, the reflected rediation will be shifted in frequency, since the grating is moving. A twofold increase of the frequency is readily attainable. It is shown that it is impossible to generate radiation, because the alternating electromagnetic fields that accompany the beats cannot reform themselves into freely propagating waves. The frequency shifter is useless as a practical device, because its reflectance is extremely low for realizable beams.

Lichtenstein, R. M.↗

NASA NTRS1991

High-power converters for space applications

Phase 1 was a concept definition effort to extend space-type dc/dc converter technology to the megawatt level with a weight of less than 0.1 kg/kW (220 lb./MW). Two system designs were evaluated in Phase 1. Each design operates from a 5 kV stacked fuel cell source and provides a voltage step-up to 100 kV at 10 A for charging capacitors (100 pps at a duty cycle of 17 min on, 17 min off). Both designs use an MCT-based, full-bridge inverter, gaseous hydrogen cooling, and crowbar fault protection. The GE-CRD system uses an advanced high-voltage transformer/rectifier filter is series with a resonant tank circuit, driven by an inverter operating at 20 to 50 kHz. Output voltage is controlled through frequency and phase shift control. Fast transient response and stability is ensured via optimal control. Super-resonant operation employing MCTs provides the advantages of lossless snubbing, no turn-on switching loss, use of medium-speed diodes, and intrinsic current limiting under load-fault conditions. Estimated weight of the GE-CRD system is 88 kg (1.5 cu ft.). Efficiency of 94.4 percent and total system loss is 55.711 kW operating at 1 MW load power. The Maxwell system is based on a resonance transformer approach using a cascade of five LC resonant sections at 100 kHz. The 5 kV bus is converted to a square wave, stepped-up to a 100 kV sine wave by the LC sections, rectified, and filtered. Output voltage is controlled with a special series regulator circuit. Estimated weight of the Maxwell system is 83.8 kg (4.0 cu ft.). Efficiency is 87.2 percent and total system loss is 146.411 kW operating at 1 MW load power.

Park, J. N.↗

DOE OSTI2025

A Guide to Current Limiting and Stability with Grid-Forming Inverters

The electric power grid is changing. For many decades, the synchronous generator - an electromechanical device invented in 1887 - has been the workhorse and backbone of power grids across the globe. Our entire infrastructure is built around it. But times change, and so does the power grid. Since the early 21st century, we have seen a gradual shift in modern power grids away from synchronous generators to ones dominated by power electronic inverter-based resources (IBRs). Sources such as photovoltaics, wind turbines, battery storage, fuel cells, and other technologies like high-voltage DC transmission interconnections all rely on an inverter to connect and interface with the grid. They are increasingly being installed on the grid to augment, or even replace, traditional energy sources. This change is a fundamental shift that brings tremendous technical challenges and questions: Can a power grid remain stable with many more inverter-based resources? How do we avoid more blackouts on the grid? How do we keep the grid secure and resilient during disturbances? After all, power electronic inverters are nothing like the big, rotating, iron-and-copper machines that the grid heavily relies on. Many of these questions can be answered by using grid-forming (GFM) inverters, yet many research challenges remain. This document explores GFM inverters and how they can help stabilize the future grid, especially during disturbances and contingencies. It summarizes a two-year research and development fellowship program at NREL. We point interested readers to more detailed works developed during the project along the way. Let's dive in

24 POWER TRANSMISSION AND DISTRIBUTION↗

NASA NTRS2000

Trajectory Orientation: A Technology-Enabled Concept Requiring a Shift in Controller Roles and Responsibilities

The development of a decision support tool (DST) for the en-route domain with accurate conflict prediction time horizons of 20 minutes has introduced an interesting problem. A 20 minute time horizon for conflict prediction often results in the predicted conflict occurring one or more sectors downstream from the sector controller who "owns" (i-e., is responsible for the safe separation of aircraft) one or both of the aircraft in the conflict pair. Based on current roles and responsibilities of today's en route controllers, the upstream controller would not resolve this conflict. In most cases, the downstream controller would wait until the conflicting aircraft entered higher sector before resolving the conflict. This results in a delay of several minutes from the time when the conflict was initially predicted. This delay is inefficient from both a controller workload and user's cost of operations perspective. Trajectory orientation, a new concept for facilitating an efficient, conflict-free flight path across several sectors while conforming to metering or miles-in-trail spacing, is proposed as an alternative to today's sector-oriented method. This concept necessitates a fundamental shift in thinking about inter-sector coordination. Instead of operating independently, with the main focus on protecting their internal airspace, controllers would work cooperatively, depending on each other for well-planned, conflict-free flow of aircraft. To support the trajectory orientation concept, a long time horizon (15 to 20 minutes) for conflict prediction and resolution would most likely be a primary requirement. In addition, new tools, such as controller-pilot data link will be identified to determine their necessity and applicability for trajectory orientation. Finally, with significant controller participation from selected Air Route Traffic Control Centers, potential shifts in R-side/D-side roles and responsibilities as well as the creation of a new controller position for multi-sector planning will be examined to determine the most viable solutions.

Leiden, Ken↗

DOE OSTI2024

Strategically Modified Ligand Incorporating Mixed Phosphonate and Carboxylate Groups to Enhance Performance in All-Iron Redox Flow Batteries

Iron redox flow batteries (Fe-RFBs) hold significant promise for achieving cost-effectiveness and utilizing abundant materials for stationary energy storage applications. Here, a design of a novel Fe complex utilizing a nitrogenous phosphonate/carboxylate mixed ligand, N,N-Bis(phosphonomethyl)glycine (BMPG), is presented to achieve high performance Fe anolyte. Compared to its all-phosphonate form, nitrilotri(methylphosphonic acid) (NTMPA), the new complex Fe(BPMG) 2 demonstrates a negatively shifted redox potential, resulting in ≈0.07 V (≈10%) increase in battery output voltage. Full battery testing paired with ferrocyanide catholyte demonstrates stable cycling (capacity degradation <0.0001%/cycle) over 730 consecutive charge/discharge cycles with Coulombic Efficiency of 100% at a current density of 20 mA cm -2 under near neutral pH (≈8). Of particular interest, density functional theory (DFT) studies and operando Raman measurements provide strong evidence supporting a molecular structure in BPMG, which reveals the mixed phosphonate/carboxylate groups in BPMG maintain the octahedral coordination of the Fe ion center with phosphonates exclusively, while leaving the carboxylate unbound for both Fe(II) and Fe(III) complexes. This structural similarity between BPMG-based Fe(II) and Fe(III) complexes effectively mitigates the slow redox reaction kinetics observed in Fe(NTMPA) 2 anolyte, where significant ligand reorientation occurs between Fe(II) and Fe(III) complexes.

25 ENERGY STORAGE↗

DOE OSTI2020

Predicting Geometric Influences in Metal Additive Manufacturing

Metal additive manufacturing (AM) has evolved from scientific curiosity to a potential paradigm shift in materials manufacturing owing to its ability to control microstructure and fabricate complex geometries. However, geometry, often ignored as a variable, can have a significant impact on microstructure evolution, thereby indirectly limiting the design flexibility offered by AM. Currently, the process of retaining microstructure with changing geometry relies on trial and error-based processing followed by microstructural evaluation that places significant demands on time and costs associated with experimentation and characterization. We demonstrate herein that lightweight thermal models can be effectively used to predict microstructural changes with geometry. These models can in turn be used as precursors to developing geometry independent scan strategies and achieve microstructure control in various alloy systems. Even if the thermal signatures predicted by the model are not accurate, scan strategies can be developed to mimic the thermal conditions during initial process development. We present a case study on one of the most studied AM alloys: Ti-6Al-4V.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Catalyzing deep decarbonization with federated battery diagnosis and prognosis for better data management in energy storage systems

Industrial data analytics methods play a central role in improving energy storage performance and efficiency, impacting the future of electrified transportation and renewable electricity generation. However, significant challenges hinder the large-scale deployment of batteries. Conventional methods rely on centralized collection and processing of fleet-level data, leading to database size issues and privacy concerns due to potential data breaches. To enable scalable deployment of battery management systems, this article proposes a federated battery diagnosis and prognosis model, which distributes the processing of battery standard current-voltage-time-usage data in a privacy-preserving manner. Instead of transferring the raw data, this approach communicates only the locally processed parameters, thus reducing communication load and preserving data confidentiality. The federated model offers a paradigm shift in battery health management through privacy-preserving distributed methods for battery data processing and lifetime prediction, ensuring the reliable and sustainable deployment of lithium-ion batteries in a rapidly evolving world.

asset health management↗

DOE OSTI2017

Future changes in the climatology of the Great Plains low-level jet derived from fine resolution multi-model simulations

The southerly Great Plains low-level jet (GPLLJ) is one of the most significant circulation features of the central U.S. linking large-scale atmospheric circulation with the regional climate. GPLLJs transport heat and moisture, contribute to thunderstorm and severe weather formation, provide a corridor for the springtime migration of birds and insects, enhance wind energy availability, and disperse air pollution. We also assess future changes in GPLLJ frequency using an eight member ensemble of dynamically-downscaled climate simulations for the mid-21st century. Nocturnal GPLLJ frequency is projected to increase in the southern plains in spring and in the central plains in summer, whereas current climatological patterns persist into the future for daytime and cool season GPLLJs. The relationship between future GPLLJ frequency and the extent and strength of anticyclonic airflow over eastern North America varies with season. Most simulations project a westward shift of anticyclonic airflow in summer, but uncertainty is larger for spring with only half of the simulations suggesting a westward expansion. Furthemore, the choice of regional climate model and the driving lateral boundary conditions have a large influence on the projected future changes in GPLLJ frequency and highlight the importance of multi-model ensembles to estimate the uncertainty surrounding the future GPLLJ climatology.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Unravelling the mechanism of pressure induced polyamorphic transition in an inorganic molecular glass

The atomic structure of a germanium doped phosphorous selenide glass of composition Ge 2.8 P 57.7 Se 39.5 is determined as a function of pressure from ambient to 24 GPa using Monte-Carlo simulations constrained by high energy x-ray scattering data. The ambient pressure structure consists primarily of P 4 Se 3 molecules and planar edge shared phosphorus rings, reminiscent of those found in red phosphorous as well as a small fraction of locally clustered corner-sharing GeSe 4 tetrahedra. This low-density amorphous phase transforms into a high-density amorphous phase at ~6.3 GPa. The high-pressure phase is characterized by an extended network structure. The polyamorphic transformation between these two phases involves opening of the P 3 ring at the base of the P 4 Se 3 molecules and subsequent reaction with red phosphorus type moieties to produce a cross linked structure. The compression mechanism of the low-density phase involves increased molecular packing, whereas that of the high pressure phase involves an increase in the nearest-neighbor coordination number while the bond angle distributions broaden and shift to smaller angles. The entropy and volume changes associated with this polyamorphic transformation are positive and negative, respectively, and consequently the corresponding Clapeyron slope for this transition would be negative. This result has far reaching implications in our current understanding of the thermodynamics of polyamorphic transitions in glasses and glass-forming liquids.

42 ENGINEERING↗

DOE OSTI2022

Revisiting the K-edge X-ray absorption fine structure of Si, Ge–Si alloys, and the isoelectronic series: CuBr, ZnSe, GaAs, and Ge

Extended X-ray absorption fine structure (EXAFS) has evolved into an unprecedented local-structure technique that is routinely used to study materials’ problems in the biological, chemical, and physical sciences. Like many other experimental techniques, EXAFS also requires that several key atomic parameters must be known a priori before structural information can be quantitatively determined. Utilizing current analytical methods, we revisit the isoelectronic series CuBr, ZnSe, GaAs, and Ge originally studied by Stern et al. during the early development of EXAFS. We demonstrate that the ab initio EXAFS code FEFF accurately predicts the atomic phase shifts and backscattering amplitudes that are primarily functions of the sum of atomic numbers Z along an EXAFS scattering path. We also investigate quantitative fitting and first- and second-shell phase transferability together with problems that arise if a backscattering atom is identified incorrectly in an EXAFS fitting model. Features in the near-edge region, on the other hand, are shown to require a comprehensive treatment of the band structure and density-of-states, including effects of the screened Coulomb interaction between the photoelectron and core hole. Here, we demonstrate that the Bethe–Salpeter equation (BSE) accurately captures the NEXAFS (or XANES) portion of the spectrum for the isoelectronic series in addition to Si and Ge–Si alloys, including within a few eV of the absorption edge, where band structure and excitonic effects are most important.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

57 Fe nuclear resonance vibrational spectroscopic studies of tetranuclear iron clusters bearing terminal iron( III )–oxido/hydroxido moieties

57 Fe nuclear resonance vibrational spectroscopy (NRVS) has been applied to study a series of tetranuclear iron ([Fe 4 ]) clusters based on a multidentate ligand platform (L 3− ) anchored by a 1,3,5-triarylbenzene linker and pyrazolate or (tertbutylamino)pyrazolate ligand (PzNH t Bu − ). These clusters bear a terminal Fe(III)–O/OH moiety at the apical position and three additional iron centers forming the basal positions. The three basal irons are connected with the apical iron center via a μ 4 -oxido ligand. Detailed vibrational analysis via density functional theory calculations revealed that strong NRVS spectral features below 400 cm −1 can be used as an oxidation state marker for the overall [Fe 4 ] cluster core. The terminal Fe(III)–O/OH stretching frequencies, which were observed in the range of 500–700 cm −1 , can be strongly modulated (energy shifts of 20–40 cm −1 were observed) upon redox events at the three remote basal iron centers of the [Fe 4 ] cluster without the change of the terminal Fe(III) oxidation state and its coordination environment. Therefore, the current study provides a quantitative vibrational analysis of how the remote iron centers within the same iron cluster exert exquisite control of the chemical reactivities and thermodynamic properties of the specific iron site that is responsible for small molecule activation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2017

Constraining the baryon-dark matter relative velocity with the large-scale 3-point correlation function of the SDSS BOSS DR12 CMASS galaxies

We search for a galaxy clustering bias due to a modulation of galaxy number with the baryon-dark matter relative velocity resulting from recombination-era physics. We find no detected signal and place the constraint bv <0.01 on the relative velocity bias for the CMASS galaxies. This bias is an important potential systematic of Baryon Acoustic Oscillation (BAO) method measurements of the cosmic distance scale using the 2-point clustering. Our limit on the relative velocity bias indicates a systematic shift of no more than 0.3% rms in the distance scale inferred from the BAO feature in the BOSS 2-point clustering, well below the 1% statistical error of this measurement. In conclusion, this constraint is the most stringent currently available and has important implications for the ability of upcoming large-scale structure surveys such as DESI to self-protect against the relative velocity as a possible systematic.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2024

Limit Cycle Oscillating Detonation Wave Behavior Analysis Within a Rotating Detonation Engine

Limit cycle oscillation (LCO) detonation wave behaviors are presented and analyzed for test times exceeding 20 s in a water-cooled rotating detonation engine (RDE). LCO detonation waves exhibit cyclic acceleration and deceleration, resulting in oscillating wave spacing at unique process conditions. In previous RDE studies, similar behaviors have been studied as microsecond-scale instabilities leading to ascending or descending modal transitions. In the current work, however, LCO waves are considered a persistent wave mode, occupying unique portions of the operational envelope adjacent to those of their equally spaced counterparts. These occurrences of LCO waves are repeatable, enduring behaviors. A method to generate shifted contour surfaces specifically intended to extract and analyze wave spacing variation through time, termed limit cycle oscillation visualization (LCOV) surfaces, is presented. LCOV surfaces transform data into the reference frame of a primary traveling wave and are used to analyze quasi-steady, short-timescale, and transitional LCO modes. Results are leveraged to understand the relationship between fill height, wave strength, local wave acceleration, and subsequent LCO wave spacing for individual wave sets. In conclusion, quasi-steady LCO waves display wave spacing oscillations between equal spacing values associated with ±1 wave across runs exceeding 18 s.

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2022

Ocean Deacidification Technologies for Marine Aquaculture

The increase in partial pressure of CO 2 in the oceans directly affects the productivity and survival of coastal industries and ecosystems. For marine aquaculture, the decreased alkalinity of seawater results in reduced availability of carbonates for marine organisms to build their shells, leading to decreased aquaculture quality and productivity. The industry has been implementing recirculating aquaculture systems (RASs) to reduce CO 2 in feedwaters, but recent interest in ocean-based CO 2 capture has led to additional strategies that may be relevant. The new methods in addition to CO 2 removal offer capture options for enhanced aquaculture sustainability. Here, we review and compare early-stage and commercially available technologies for deacidification of seawater and their suitability for aquaculture. Most methods considered rely on a voltage-induced pH swing to shift the carbonate/bicarbonate equilibrium toward the release of CO 2 , with subsequent capture of the released CO 2 as a gas or as solid mineral carbonates. The modular design and distributed deployment potential of these systems offers promise, but current demonstrations are limited to bench scale, highlighting the need for sustained research and development before they can be implemented for marine aquaculture.

42 ENGINEERING↗

DOE OSTI2017

The Role of the CMB in Redshift Related Departures from the Gao–Solomon Relation

A strong correlation between the far-IR and HCN(1−0) line luminosities, known as the Gao–Solomon relation, has been observed to hold over more than 10 orders of magnitude in the local universe. Departures from this relation at redshifts ≳1.5 have been interpreted as evidence for increased dense gas star formation efficiency in luminous galaxies during the period of peak of star formation in the history of the universe. We examine whether the offsets from the relation can be explained by the hotter Cosmic Microwave Background (CMB) at high redshift, which, due to a loss of contrast against the hotter background, reduces the observable molecular-line flux far more significantly than the far-IR continuum bands. Simple line-of-sight modeling argues for highly significant departures from the Gao–Solomon relation at high redshift for kinetic temperatures ∼15 K, while more complex toy-galaxy models based on NGC 1068 suggest a much weaker effect with the galaxy integrated HCN line flux falling by only 10% at z = 3, within the intrinsic scatter of the relation. We conclude that, while the CMB is unlikely to explain the deviations reported in the literature, it may introduce a second-order effect on the relation by raising the low-luminosity end of the Gao–Solomon relation in cooler galaxies. A similar examination of the CO-IR relation finds tantalizing signs of the CMB having a measurable effect on the integrated CO emission in high-redshift galaxies, but these signs cannot be confirmed with the current data.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2023

Does Feedback from Supermassive Black Holes Coevolve with the Host in Type 2 Quasars?

The feedback from the accretion of central supermassive black holes (SMBHs) is a hot topic in the coevolution of SMBHs and their host galaxies. By tracing the large-scale outflow using the line profile and bulk velocity shift of [O III ]λ5007, the evolutionary role of outflow is studied here on a large sample of 221 type 2 quasars (QSO2s) extracted from Reyes et al. By following our previous study on local Seyfert 2 galaxies, the current spectral analysis on the Sloan Digital Sky Survey spectroscopic database enables us to arrive at the following results: (1) by using the Lick indices, we confirm that QSO2s are, on average, more frequently associated with younger stellar populations than Seyfert galaxies; (2) QSO2s with a stronger outflow tend to be associated with a younger stellar population, which implies a coevolution between the feedback from SMBHs and the host in QSO2s; (3) although occupied at the high L bol /L Edd end, the QSO2s follow the L bol /L Edd -D n (4000) sequence established from local, less-luminous Seyfert galaxies, which suggests a decrease of the accretion activity of SMBHs and also of feedback as the circumnuclear stellar population continuously ages.

79 ASTRONOMY AND ASTROPHYSICS↗